1. Field of the Invention
The present invention relates to record/playback heads intended in use to cooperate with a flexible record medium with an air bearing therebetween.
2. Description of the Prior Art
For successful data recording, particularly at high densities, such as employed in storage apparatus for use with digital computers and data communication links, there should be a predictable constant spacing between a record medium and a record/playback head over a wide range of operating parameters. More specifically there should be a predictable constant spacing between a record medium and the transducing element of the record/playback head used therewith. Thus, in the case of magnetic recording, for example, the spacing between the medium and the magnetic gap of the head has a substantial effect on the fringing flux pattern and hence the resolution of the sensing and recording of data on the recording medium.
In storage apparatus employing flexible record media, the interaction of many parameters has a substantial effect on the predictability and maintainability of such desired constant spacing. The parameters affecting such spacing include the contour of the head surface facing the record medium, the penetration depth of the head and hence the transducing element into the plane of rotation of the record medium, the relative speed between head and record medium, the radial position of the head (in a disk recorder), the medium parameters such as flexibility and thickness, the orientation, or angle of attack of the transducer with respect to the record medium, the size of the head, and environment factors such as temperature and humidity. Additionally, with a storage apparatus, such as that in which a record/playback head is moved over a record medium in an arc by a pivoted elongated arm driven by an electro-mechanical means such as a motor or other device, the parameter of `yaw` is introduced. As is used herein, "yaw" means the angle subtended between a track along which the head lies and the transducer gap. With a pivoted actuator `yaw` continuously changes as the head moves over the disk surface during access operations. Furthermore, with apparatus in which the recording medium is contained in a cartridge which is loaded onto a drive unit during use and is interchangeable with other like cartridges, slight variations in tolerances at the mechanical interface cause variations in head penetration into the plane of rotation of the flexible medium. It is desirable therefore, for the medium to exhibit a fairly constant flying height over the transducing element even for a range of head penetration depths into the plane of rotation of the medium.